The present thesis is a study of the development of gunpowder weapons in Late Medieval England. This was a new technology that had reached Western Europe by the early fourteenth century, which had first supplemented and later supplanted traditional forms of artillery. The development of early firearms has long been recognised as significant by historians and has been identified as a key part of the military revolution hypothesis. As a result of this, gunpowder weapons are often discussed in general works on English military history but there is at the moment no satisfactory study on its long-term development in England. The aim of the present study is to rectify this gap in the literature by carrying out a thorough examination and comparison of the extensive surviving financial records for the English Crown and towns for the period covering the reigns of Edward III to Henry VII. This information will be analysed to determine how the use of guns on military campaigns, in towns, royal fortifications and on ships changed over time, as well as to assess what factors influenced the development of gunpowder weapons and to see if these changes constituted a military revolution. As a result of this research, it is now possible to establish a comprehensive narrative of how English gunpowder weapons developed throughout this critical period in the history of the technology.